If you want more than one document, I recommend you look at this post by @Eyescream which refers to blog posts by Jeff Douglass and a Helper Class that creates a map of the pages to be rendered as a single attachment. It's an answer to a question describing a solution someone came up with for doing the type of thing you describe.
For a single document, if you don't want to preview the document, use getContentAsPDF in a custom button to add it to an email template. If you want to preview the PDF first, see @MichaelWelburn Blog Post on how to do it via a button. You may also want to view @CA_Peterson's answer to How to download a VF page as PDF and email it from a trigger?.
Another post that may be of interest would be too many nested getContent calls?.